"That was so adorable," Marbles said in the video, posted on December 6.

"Put that in," Solomita urged.

"He's so cute. He was eating a cup of sprinkles and throwing a ball," Marbles added.

After realising how famous the pair were moments after leaving them, Joey sprinted back.

Julien Solomita and Jenna Marbles gave the schoolboy a shout out to Marbles' 17 million followers. (YouTube) ()

"You have a million [subscribers]?," the exasperated 12-year-old asked.

"This is freaking me out… I am talking to professional YouTubers," he exclaimed while politely apologising for bothering the pair.

Marbles urged her subscribers to follow the budding young vlogger, as long as they were "very kind and supportive".

The next day the 12-year-old had 12,000 new followers. Three weeks later, he has more than 90,000.

His excitement was captured in an adorable video taken by his parents the morning after his account blew up.

Joey's excitement was captured in an adorable video taken by his parents the morning after his account blew up. (YouTube) ()

The schoolboy can be seen pacing around the lounge room, checking his account and soaking up his new- found fame.

Joey thanked Solomita and Marbles for their contribution, and also gave another teen vlogger with a very similar username a shout out for not trying to claim his viral fortune.

YouTube stars have proven vlogging is big business, with top performers raking in millions of dollars.

The richest YouTuber in the world, Minecraft player Daniel Middleton, is an uber-celebrity among 11-year-olds, yet would have little trouble walking down any street in the world without being recognised.

His channel DanTDM boasts more than 11 billion views and nets him an estimated $16.5 million a year.

Other entrants on Forbes’ richest YouTubers list include an eight-year-old who has made $11 million from reviewing toys and the stunt group Dude Perfect, which pulled in an impressive $14 million.